Insulated, soft-sided coolers, lunch bags and similar containers are a popular item to carry on a picnic, trip or to an event. They are available in a wide range of sizes and shapes. Many are constructed from cloth or polymer sheet outer shell with a liner that resists moisture. The liner may be removable, or permanently attached. Between the liner and the outer shell is often disposed an insulating material, though an empty air space therebetween is also a relatively good insulator, absent a filler material.
Most coolers and lunch bags include a sealed lid that retains the container's content's and reduces heat transfer between the bag interior and the external environment. The lid may be a simple flap that overlap's the container's side(s) and is secured by a fastener (e.g. hook-and-loop material, a snap, etc.). Alternatively, the lid may be a closely fitted flap of insulated material that hinges on a side of the container and is secured to the adjacent sides of the container by a zipper or similar type of continuous securing mechanism. This type of continuous seal is quite effective at reducing heat transfer.
While soft-sided, insulated containers may typically be flattened for storage, this may cause them to deform, and become permanently wrinkled over time. As such, it may prove harder to place items efficiently within the container's interior after it is unflattened, and the container may display an undesirable, rumpled shape.
It is, thus, desirable to provide a container that flattens to minimize its volume when not in use, but that can be immediately placed in an expanded shape that does not suffer from permanent wrinkles or deformation due to flattening. It is also desirable to provide a unique lid construction that is unaffected by the flattening of the container, and that restricts unwanted heat transfer and moisture loss.